(1^2+3^2+5^2+......+99^2)-(2^2+4^2+6^2+......+100^2)
=1^2+3^2+5^2+......+99^2-2^2-4^2-6^2-......-100^2
=1^2-2^2+3^2-4^2+....+99^2-100^2
=(1-2)(1+2)+(3-4)(3+4)+...+(99-100)(99+100)
=-1-2-3-4-...-99-100
=-(1+2+3+4+...+100)
=-(101*50)
=-5050
原式=(1^2-2^2)+(3^2-4^2)+……+(99^2-100^2)
=[(1-2)(1+2)]+[(3-4)(3+4)]+……+[(99-100)(99+100)](重组后用平方差)
=-[(1+2)+(3+4)+……+(99+100)]
=-[1+2+……+100)] (这一步形成高斯连加)
=-5050
简单啊
原式=-[(2^2-1^2)+(4^2-3^2).....+(100^2-99^2)]
=-[(2-1)(2+1)+(4-1)(4+3).....(100-1)(100+99)]
=-[1+2+3+4+......+99+100]
=-[(1+100)*100/2]
=-5050
(1^2+3^2+5^2+......+99^2)-(2^2+4^2+6^2+......+100^2)
=(1^2-2^2)+(3^2-4^2)+......+(99^2-100^2)
=-(1+2+3+4+......+99+100)
=-5050
:(1^2+3^2+5^2+......+99^2)-(2^2+4^2+6^2+......+100^2)
=(1^2-2^2)+(3^2-4^2)+...+(99^2-100^2)
=(1+2)(1-2)+(3+4)(3-4)+...+(99+100)(99-100)
=-(1+2+3+4+...+99+100)
=-5050